Bag Opening Apparatus for Filling Vertically Positioned Horizontally Traversing Plastic Film Bags

ABSTRACT

In an automated machine that forms a vertically positioned and horizontally traversing web of plastic film into bags and fills the bags with material, the apparatus opens the bags by separating the bag upper longitudinal edge portions. First and second opposing slide gates on opposite sides of the bags normal traversing plane are moveable between closed and open positions. Longitudinal channels on each of the slide gates receive and clampingly grip the bag longitudinal edge portions when the gates are moved away from their closed positions. The bag edge portions are thereby gripped and separated from one another when the gates are opened for thereby opening and filling the bags. While opening the gates, additional longitudinal edge portions are pulled into the apparatus and, while closing the gates, the additional edge portions are pulled out therefrom. The longitudinal edge portions freely traverse through the channels when the gates are closed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of automated machines thatform a vertically positioned and horizontally traversing web of plasticfilm into bags and fill the bags with material. More particularly, thepresent invention relates to an apparatus that opens the bags byseparating the bag upper longitudinal edge portions leading to the bagopening and delivers a quantity of material therethough into the bagcavity.

2. Background

Automated machines that form a web of plastic film into bags and fillthem with material are today commonly known and used. Some of thesemachines also utilize a plastic film web that is situated vertically andfed into the machine horizontally. Examples of such machines are shownin: U.S. Pat. No. 2,853,842; U.S. Pat. No. 2,885,846; U.S. Pat. No.3,241,290; U.S. Pat. No. 3,359,703; U.S. Pat. No. 3,597,895; U.S. Pat.No. 3,699,746 U.S. Pat. No. 3,753,332; and, U.S. Pat. No. 4,617,785.

Although the prior known machines are satisfactory, a need exists for amachine that forms a vertically positioned horizontally fed web ofplastic film into bags and fills the bags with material and which has arelatively high output, takes a relatively small footprint, and is moreefficient and reliable.

SUMMARY OF THE INVENTION

The present invention overcomes disadvantageous of prior automatedplastic film bag forming and filling machines and provides additionaladvantageous and benefits as described hereinbelow.

In one form thereof the present invention is directed to an apparatusfor opening and filling vertically positioned plastic film bagstraversing horizontally along a normal traversing plane from an upstreamlocation to a downstream location, wherein the bags include a pair ofparallel proximate longitudinal edge portions defining a bag openingtherebetween leading to a bag cavity vertically therebelow. Theapparatus includes a first gate on one side of the normal traversingplane selectively moveable between a closed position adjacent the normaltraversing plane and an open position at a distance away from the normaltraversing plane. A second gate is provided on the other side of thenormal traversing plane opposing the first gate and selectively moveablebetween a closed position adjacent the normal traversing plane and anopen position at a distance away from the normal traversing plane. Eachof the first and second gates include a longitudinal channel receivingone of the bag longitudinal edge portions therethough. The longitudinalchannels allow the bag edge portions to traverse therethrough when thegates are in their closed position and clampingly grip the bag edgeportions when the gates are away from their closed position. When thegates are in their open positions, the bag longitudinal portions aregripped and separated from one another for thereby opening and fillingthe bag and, when the gates are in their closed positions, the baglongitudinal portions are released and allowed to longitudinallytraverse through their respective longitudinal channel.

Preferably, each of the longitudinal channels is formed between aleading gate plate and a selectively moveable clamp bar, and the clampbar is moveable away from the leading gate plate when the gate is in itsclosed position thereby opening the longitudinal channel and allowingthe bag edge portion to traverse therethrough, and is also moveableagainst the leading gate plate when the gate is away from its closedposition thereby closing the longitudinal channel and clampingly gripingthe bag edge portion therebetween. One or more springs are used to movethe clamp bar against the leading gate plate when the gate is away fromits closed position. A pneumatic cylinder is coupled to each of thefirst and second gates and are selectively actuable for moving the gatesto their closed and open positions.

Also preferably, while the gates are being moved from their closedpositions to their open positions, additional longitudinal edge portionsare pulled into the apparatus from at least one of the upstream anddownstream locations and, while the gates are being moved from theiropen positions to their closed positions, the additional longitudinaledge portions are pulled out of the apparatus towards at least one ofthe upstream and downstream locations. A dancer bar assembly is providedat the upstream location and provides tension is the longitudinal edgeportions and pulls the additional edge portions out of the apparatuswhile the gates are being closed. A gripping and pulling assembly isprovided at the downstream location and pulls the additional edgeportions out of the apparatus while the gates are being closed.

More preferably, the additional longitudinal portions at the upstreamlocation extend through a pair of upstream clamping members and theadditional longitudinal portions at the downstream location extendthrough a pair of downstream clamping members and, while the gates arein their closed positions, the upstream and downstream clamping membersallow the additional longitudinal portions to traverse therethrough and,while the gates are in their open positions, the upstream and downstreamclamping members clampingly grip and prevent the additional longitudinalportions to traverse therethrough. The clamping members are preferablyrubber rollers and, while the gates are opening and closing, the rollersguide the additional longitudinal edges as they traverse therethrough.

Yet more preferably, a bulk material measuring apparatus is providedand, when the gates are in their open positions, a quantity of bulkmaterial is delivered between the gates, through the bag opening andinto the bag cavity. Also, the plastic film bags are formed from a webof plastic film folded along a central longitudinal fold line therebydefining the pair of parallel proximate longitudinal edge portions.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features and objects of this invention,and the manner of attaining them, will become more apparent and theinvention itself will be better understood by reference to the followingdescription of the embodiments of the invention taken in conjunctionwith the accompanying drawings, wherein:

FIG. 1 is a perspective view of a horizontally fed vertically hangingplastic film forming and filling machine constructed in accordance withthe principles of the present invention along with a bulk materialfeeding apparatus;

FIG. 2 is another perspective view of the machine and the bulk materialfeeding apparatus shown in FIG. 1;

FIG. 3 is a perspective view of the horizontally fed vertically hangingplastic film terming and filling machine shown in FIG. 1 from a positionviewing the front, top and left side and with the controls cabinet andinterface control module removed;

FIG. 4 is a perspective view of the machine shown in FIG. 3 from aposition viewing the top, front and right side;

FIG. 5 is a front elevation view of the machine shown in Fig, 3 andfurther diagrammatically showing a plastic film web being formed into acontinuous web of bags and the bags being filled with bulk material andbeing sealed closed;

FIG. 5a is a cross-sectional view of the plastic film web taken alongline 5 a-5 a of FIG. 5;

FIG. 5b is an elevation view of a portion of the plastic film web afterit has been formed into a web of bags connected to one another along anupper longitudinal edge portion;

FIG. 5c is a cross-sectional view of the upper longitudinal portionconnecting the web of formed bags taken along line 5 c-5 c of FIG. 5 b;

FIG. 5d is a cross-sectional view of the web of formed bags taken alongline 5 d-5 d of FIG. 5 b;

FIG. 6 is a rear elevation view of the machine shown in FIG. 3;

FIG. 7 is perspective view of the machine shown in FIG. 3 from aposition viewing the bottom, front and left side;

FIG. 8 is a perspective view of the machine shown in FIG. 3 from aposition viewing the bottom, front and right side;

FIG. 9 is a front elevation view of the dancer bar assembly of themachine shown in FIG. 3 as it is mounted in the machine frame and with apart of the frame removed, and diagrammatically showing the plastic filmweb traversing therethrough;

FIG. 10 is a perspective view of the dancer bar assembly shown in FIG. 9and being shown removed from the machine frame, and alsodiagrammatically showing the top edge of the plastic film web traversingtherethrough and over the rollers;

FIG. 11a is an elevation view of the stationary roller of the dancer barassembly shown in FIG. 10;

FIG. 11b is an elevation view of the movable roller of the dancer barassembly shown in FIG. 10;

FIG. 12a is a perspective view of the perforation and sides sealassembly of the machine shown in FIG. 3 from a position showing theright/upstream side, rear, and bottom;

FIG. 12b is another perspective view of the perforation and sides sealassembly of the machine shown in FIG. 3 from a position showing thefront, left/downstream side, and bottom;

FIG. 13a is a cross-sectional view of the perforation and sides sealassembly taken along line 13-13 of FIG. 6 and showing the heat seal barand perforation knife in their retracted positions;

FIG. 13b is a cross-sectional view of the perforation and sides sealassembly taken along line 13-13 of FIG. 6 and showing the heat seal barand perforation knife in their extended positions;

FIG. 14 is a perspective view of the perforation knife subassembly ofthe perforation and sides seal assembly;

FIG. 15 is an exploded view of the perforation knife subassemblycomponents shown in FIG. 14;

FIG. 16a is a side view of the perforation knife subassembly shown inFIG. 14 and showing the perforation knife in its retracted position;

FIG. 16b is a side view of the perforation knife subassembly shown inFIG. 14 and showing the perforation knife in its extended position;

FIG. 17 is a perspective view of the undulating edge film guiding andsupporting assembly of the machine shown in FIG. 3;

FIG. 18a is cross-sectional view of the undulating edge film guiding andsupporting assembly taken along line 18-18 of FIG. 17 and showing thetemporary film supporting plunger in its clamped film carrying position;

FIG. 18b is a cross-sectional view similar to FIG. 18a but showing thetemporary film supporting plunger in its open released position;

FIG. 19 is a top elevation view of the undulating edge film guiding andsupporting assembly shown in FIG. 17 with the supporting plungersremoved and diagrammatically showing the plastic film webextending/travelling therethrough;

FIG. 19a is a top elevation view of an alternate undulating edge filmguiding and supporting assembly embodiment as modified from theembodiment. of FIG. 17;

FIG. 19b is a top elevation exploded view of the resulting supportingplates of the embodiment shown in FIG. 19 a;

FIG. 19c is a top elevation view of the supporting plates of anotheralternate undulating edge film guiding and supporting assemblyembodiment;

FIG. 20 is a side elevation view of the undulating edge film guiding andsupporting assembly shown in FIG. 19 secured on the machine top frameplate;

FIG. 21a is a cross-sectional view of undulating edge film guiding andsupporting assembly taken along line 21 a-21 a of FIG. 19 anddiagrammatically showing the plastic film web extending/travelingtherethrough;

FIG. 21b is a cross-sectional view of undulating edge film guiding andsupporting assembly taken along line 21 b-21 b of FIG. 19 anddiagrammatically showing the plastic film web extending/travelingtherethrough;

FIG. 21c is a cross-sectional view of undulating edge film guiding andsupporting assembly similar to FIG. 21a but depicting the supportingplates vertically offset from one another;

FIG. 21d is a cross-sectional view of undulating edge film guiding andsupporting assembly similar to FIG. 21b but depicting the supportingplates vertically offset from one another;

FIG. 22 is a perspective view of the bag opening and closing assembly ofthe machine shown in FIG. 3 from a position viewing the tell/downstreamside, bottom and front elevation;

FIG. 23 is a perspective view of the bag opening and closing assembly ofthe machine shown in FIG. 3 from a position viewing the left/downstreamside, top and front elevation;

FIG. 24a is a bottom elevation view of the bag opening and closingassembly shown in FIG. 22 and showing the sliding gates in their closedposition whereat the grippers are open and the side rollers are in theirreleased positions whereby the plastic film web upper longitudinalportions can freely traverse horizontally therethrough;

FIG. 24b is a bottom elevation view similar to FIG. 24a and showing thesliding gates partially open whereat the plastic film web upperlongitudinal portions are firmly gripped by the grippers and the siderollers are in their guiding positions allowing and guiding the film webupper longitudinal portions to be pulled therein;

FIG. 24c is a bottom elevation view similar to FIG. 24b and showing thesliding gates fully open whereat the plastic film web upper longitudinalportions are firmly gripped by the grippers and the side rollers are intheir clamped positions preventing the film web upper longitudinalportions to be pulled therein and for thereby allowing bulk material tosafely drop into the bag;

FIG. 24d is a bottom elevation view similar to FIG. 24c and showing theside rollers in their guiding positions whereby the sliding gates maythen be closed and allow the film web upper longitudinal portions to bepulled out therefrom;

FIG. 25a is a cross-sectional view taken along line 25-25 of FIG. 24aand showing the sliding gates in the position as shown in FIG. 24 a;

FIG. 25b is a cross-sectional view taken along line 25-25 of FIG. 24aand showing the sliding gates in the position as shown in FIG. 24 b;

FIG. 25c is a cross-sectional view taken along line 25-25 of FIG. 24aand showing the sliding gates in the position as shown in FIG. 24 c;

FIG. 26 is a cross-sectional view taken along line 26-26 of FIG. 24 a;

FIG. 27 is a perspective view of the bag opening and closing assembly,bag pulling and sealing assembly and vertically moving and horizontallyconveying assembly from a position showing the front, top and rightelevation, and with the machine frame and other components removed forclarity;

FIG. 28 is a front elevation view of the bag opening and closingassembly, bag pulling and sealing assembly and vertically moving andhorizontally conveying assembly shown in FIG. 27;

FIG. 29 is a perspective view of the heat sealing subassembly of the bagpulling and sealing assembly shown in FIG. 27;

FIG. 30 is a top plan view of the heat sealing subassembly shown in FIG.29;

FIG. 31a is a cross-sectional view taken along line 31 a-31 a of FIG. 30and showing the heat bars of heat sealing subassembly in their retractedopen position;

FIG. 31b is a cross-sectional view taken along line 31 a-31 a of FIG. 30and showing the heat bars of heat sealing subassembly in their extendedclosed position;

FIG. 32 is a perspective view of the gripping and pulling subassembly ofthe bag pulling and sealing assembly shown in FIG. 27;

FIG. 33 is a perspective view of the gripper fingers of the gripping andpulling subassembly shown in FIG. 32;

FIG. 34a is a top plan view of the gripper fingers shown in FIG. 33 andshowing the gripper fingers in their open/release position;

FIG. 34b is a top plan view of the gripper fingers similar to FIG. 34aand showing the gripper fingers in their closed/gripping position; and,

FIGS. 35a-35d are front elevation views of the bag opening and closingassembly, vertically moving and horizontally conveying assembly, heatsealing subassembly and the gripper fingers of the gripping and pullingsubassembly with all other machine components removed for clarity, andshowing the process of operation of the vertically moving andhorizontally conveying assembly.

Corresponding reference characters indicate corresponding partsthroughout several views. Although the exemplification set out hereinillustrates embodiments of the invention, in several forms, theembodiments disclosed below are not intended to be exhaustive or to beconstrued as limiting the scope of the invention to the precise formsdisclosed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring initially to FIGS. 1 and 2, there is shown a horizontally fedvertically hanging plastic film bags forming and filling machine 10 anda bulk material feeding apparatus 12. Apparatus 12 measures desiredquantities of bulk material such as, for example, mulch, peat moss,sawdust, insulation, compost, corn, grains, etc., and selectivelydischarges the measured bulk material through a chute 14 into themachine 10. The machine 10, as described herein below, forms plasticfilm bags, selectively receives and loads the pre-measured bulk materialinto the bags and then seals the bags closed. Machine 10 includes acontrols cabinet 11 and an operator interface control module 13 (notshown in the other drawings for clarity) whereby the machine 10 andapparatus 12 are controlled as needed or desired.

Referring now also to FIGS. 3-8, machine 10 includes: a plastic filmroll supporting and feeding assembly 16; a dancer bar assembly 18; aperforation and sides seal assembly 20; an undulating edge film guidingand supporting assembly 22; a bag opening and closing assembly 24; a bagpulling and sealing assembly 26; and, a bag vertically moving andhorizontally conveying assembly 28. Assemblies 16, 18, 20, 22, 24, 26and 28 are supported on a frame comprising horizontal lower beams 32L,32R and horizontal upper beams 34L, 34R which extend between and aresupported on rectangular end tube members 30L, 30R. The beams 32L, 32R,34L, 34R and end members 30L, 30R are preferably made of steel. A steelframe plate 100 is secured between the upper beams 34L, 34R and theupper horizontal tubes of end members 30L, 30R.

The process of forming and filling of the plastic film bags isdiagrammatically depicted and generally shown in FIGS. 5 and 5 a-5 d.The plastic film and bags are not shown in FIGS. 1-4 and 6-8 forclarity. An elongate web of plastic film 36 is provided on a roll 38which is carried on the plastic film roll supporting and feedingassembly 16. Roll 38 is positioned vertically and is adapted to rotateabout its central axis 40 so that, as the plastic film web 36 isunwound/removed from the roll 38, it travels into the machine 10 in ahorizontal direction as depicted by arrow 42. The plastic film web 36is, therefore, also positioned vertically and generally parallel withthe roll central axis 40.

The web of plastic film 36 comprises an elongate web of plastic filmwhich has been folded along a longitudinal central fold line 44 andwhich thereby defines a pair of plastic film walls 46L, 46R extendingbetween the film fold line 44 and respective longitudinal edges 481,48R. The plastic film web 36 is, therefore, U-shaped as viewed in crosssection (FIG. 5a ) with the walls 46L, 46R being vertically aligned andparallel to one another, The longitudinal edges 48L, 48R arehorizontally aligned with one another and are vertically above the foldline 44.

After the plastic film web 36 is unwound/removed from the roll 38, ittravels into the machine 10 through an opening 50 in the end tube member30R, over the dancer bar assembly 18, and then through the perforationand sides seal assembly 20. At the perforation and sides seal assembly20, the web walls 46L, 46R are severed along a vertical separation 52extending from the longitudinal central fold line 44 a distance of about1 to 2 inches below the longitudinal film edges 48L, 48R. This distanceis diagrammatically depicted with a short-long dash line 54. The edgesformed along the plastic film walls 46L, 46R at the vertical separation52 are simultaneously heat sealed/fused to one another thereby creatingbag fore side seal edges 56F and bag aft side seal edges 56A. As the web36 travels through the perforation and sides seal assembly 20, thevertical separations 54 and resulting fore and aft side seal edges 56F,56A are formed at a desired distance from one another for therebyforming bags 58 defining a cavity 60 between the severed walls 46L, 46R.The bags 58 hence have a height equal to the length of the verticalseparation 52 and a width equal to the distance between their fore sideseal edge 56F and their aft side seal edge 56A.

The longitudinal edge portions 62L, 62R of the respective plastic filmwalls 46L, 46R which are located above the short-long dash line 54remain separated from one another and, hence, define a bag opening 64therebetween into the bag cavity 60. Also, at the perforation and sidesseal assembly 20, the longitudinal edge portions 62L, 62R are bothperforated along a perforation line 66 which is vertically aligned withthe vertical separation 52. The perforation lines 66 extend from abovethe vertical separation 52, essentially, from the short-long dash line54 to the plastic film longitudinal edges 48L, 48R. The perforationlines 66 essentially form vertical weakened attachment lines which areused downstream for separating the bags 58 from the web 36 after thebags have been filled and prior to heat sealing them closed.

After the perforation and sides seal assembly 20, the web 36 formed bags58 travel through the undulating edge film guiding and supportingassembly 22 to the opening and closing assembly 24. At the bag openingand closing assembly 24, the longitudinal edge portions 62L, 62R above abag 58 and between a pair of perforation lines 66 are separated from oneanother for thereby exposing the bag opening 64 and, as shown in FIG. 5,filling the bag cavity 60 with a pre-measured quantity of bulk material68 received from the bulk material feeding apparatus 12 through thechute 14. The opening and closing assembly 24 then brings thelongitudinal edge portions 62L, 62R back together/adjacent one anotherthereby closing the bag opening 64.

After the bag at the opening and closing assembly 24 has been filled andclosed, the vertically moving and horizontally conveying assembly 28conveys it under the bag pulling and sealing assembly 26 while,simultaneously, the pulling and sealing assembly 26 pulls thelongitudinal edge portions 62L, 62R therein. As the longitudinal edgeportions 62L, 62R are pulled into the pulling and sealing assembly 26,they are separated from the upstream bag 58 web 36 at the perforationline 66 therebetween. At the pulling and sealing assembly 26, the bagfilm walls 46L, 46R are heat sealed/fused to one another along a closureline 324 (FIG. 35a ) extending between the bag fore side seal edge 56Fand aft side seal edge 56A.

As further described herein below, the vertically moving andhorizontally conveying assembly 28 cooperates with the opening andclosing assembly 24 and the pulling and sealing assembly 26 andfunctions to vertically support and move and horizontally convey thebags while they are being filled, closed, heat sealed closed and,finally, removed from the machine 10. The undulating edge film guidingand supporting assembly 22 receives the plastic film longitudinalportions 62L, 62R therethrough and functions to support/carry the bags58 and maintain the plastic film longitudinal portions 62L, 62Rhorizontally aligned as the web travels into the opening and closingassembly 24. The dancer bar assembly 18 functions to maintain tension inthe plastic film longitudinal portions 62L, 62R extending between theroll 38 and the opening and closing assembly 24 as the longitudinalportions 62L, 62R travel through the perforation and sides seal assembly20 and the undulating edge film guiding and supporting assembly 22.

The plastic film roll supporting and feeding apparatus 16 includes acarriage 70 slidingly captured between vertical side beams 72L, 72Rwhich are attached to the end member 30R, and is thereby verticallymovable. A threaded rod 74 is, at its lower end thereof, threadinglycoupled to the carriage 70. The upper end of the threaded rod 74 extendsthrough the upper horizontal tube of the end member 30R and a crankhandle 76 is coupled thereto. Accordingly, the carriage 70 isselectively vertically adjustable by turning the crank handle 76 andcausing the threaded rod 74 to be received or extended. from thecarriage 70 relative to the end frame 30R.

A carriage arm 78 is attached to and extends out from the carriage 70. Aroll supporting disk 80 and a shaft drive unit 82 are mounted on and aresupported by the arm 78. The drive unit 82 is coupled to and rotatablydrives the supporting disk 80 about the vertical axis 40, in a clockwisedirection as viewed from the top, as indicated by arrow 84 (FIG. 4).Drive unit 82 is selectively energized in response to a signal from thedancer bar assembly 18 and rotatably drives the supporting disk 80 andplastic film roil 38 thereon for thereby unwinding/removing the plasticfilm web 36 as the web 36 is pulled into the machine 10 through theopening 50.

An upper roll stabilizing arm 86 is pivotally coupled to the upperhorizontal tube of the end member 30R so as to pivot about a horizontalaxis as indicated by arrow 88 (FIGS. 5 and 6). A boss 90 is rotatablycoupled to the arm 86 and is adapted to rotate about the vertical axis40. Boss 90 extends downwardly from the arm 86 and is adapted to engagethe plastic film roll 38 for stabilizing and maintaining roll 38 in itsvertical position as shown in FIG. 5 while the roll is rotatably drivenand the plastic film web 36 is unwound/removed therefrom.

As should now be appreciated, successive plastic film rolls 38 can beplaced on the supporting disk 80 by pivotally lifting the stabilizingarm 86 and boss 90 as indicated by arrow 88. Also, by turning the crankhandle 76 the vertical height of the plastic film roll 38 sitting on thesupporting disk 80 can be adjusted for horizontally aligning the plasticfilm web 36 and its longitudinal edge portions 62L, 62R with the machineassemblies 18, 20, 22, 24, 26 and 28.

As mentioned herein above, the dancer bar assembly 18 functions tomaintain tension in the plastic film longitudinal portions 62L, 62R ofthe web 36 extending between the roll 38 and the opening and closingassembly 24 as the longitudinal portions 62L, 62R travel through theperforation and sides seal assembly 20 and the undulating edge filmguiding and supporting assembly 22. The dancer bar assembly, as shown inFIGS. 10, 9, 11 a and 11 b, includes a vertical shaft 92 rotatablysecured, at its upper end, with an upper flanged bearing 96 to a platemember 98. Plate member 98 is, in turn, secured with fasteners (notshown) to an upper frame bracket 94. At its lower end, shaft 92 isrotatably secured to a frame plate 100 with a lower flanged bearing 102,The upper frame bracket 94 and the frame plate 100 are rigidly securedto the machine frame horizontal upper beams 34L, 34R and/or the endmember 30R. Accordingly, shaft 92 freely rotates about a vertical axis104 relative to the machine frame bracket 94 and frame plate 100.

An L-shaped dancer bracket 110 is secured to the shaft 92 and rotatestherewith about the vertical axis 104. L-shaped dancer bracket 110includes a roller arm 106 extending perpendicular from the shaft 92 anda spring arm 108 extending perpendicular from the shaft 92 and, also,generally perpendicular from the roller arm 106.

An upstream concave shaped film guide roller 112 is rotatably secured tothe terminal end of the roller arm 106 and freely rotates about avertical axis 114 relative to the roller arm 106, Hence, the roller 112also rotates/is movable along with the roller arm 106 about the verticalaxis 104. Roller 112 can be rotatably secured to the arm 106 as, forexample, shown with a shoulder bolt 116 extending therethough and beingthreadingly secured to the arm 106. Roller 112 is preferably made ofrubber, nylon or other suitable material adapted to engage the plasticfilm web 36. Roller 112, as best seen in the elevation view of FIG. 11b, includes an outer concave perimeter surface 118. That is, the outerdiameter of the roller 112 at its upper side 120U and at its lower side120L is greater than the outer diameter therebetween/in the center areaof the roller 112 and, preferably, the concave perimeter surface 118 issmooth, continuous and rounded as viewed in the side elevation view ofFIG. 11 b.

A downstream convex shaped film guide roller 122 is rotatably secured tothe lower terminal end of the dancer bar shaft 92, coaxially with theshaft 92, and freely rotates about the vertical axis 104 relative to theshaft 92. Hence, although roller 122 rotates about its axis 104, it isfixed/stationary relative to the upstream roller 112 which rotates/moveswith the dancer bracket arm 106.

Roller 122 can similarly be rotatably secured to the shaft 92 as, forexample, shown with a shoulder bolt 124 extending therethough and beingthreadingly secured to the shaft 92 Roller 122 is also preferably madeof rubber, nylon or other suitable material adapted to engage theplastic film web 36. Roller 122, as best seen in the elevation view ofFIG. 11a , includes an outer convex perimeter surface 126. That is, theouter diameter of the roller 122 at its upper side 128U and at its lowerside 128L is less than the outer diameter therebetween/in the centerarea of the roller 122 and, preferably, the convex perimeter surface 126is smooth, continuous and rounded as viewed in the side elevation viewof FIG. 11 a.

As best seen in FIG. 10, an extension spring 130 is provided between theterminal end of the spring arm 108 and the frame plate 100 Moreparticularly, a shoulder bolt 132 is secured to the terminal end of thearm 108 and a shoulder bolt 134 is secured to the frame plate 100, andone end of the spring 130 is coupled to bolt 132 and its other oppositeend is coupled to bolt 134. Accordingly, extension spring 130 provides aresistive bias force against the rotation of the dancer bar bracket 110when the dancer bar bracket 110 and shaft 92 are rotated in acounterclockwise direction as viewed from the top.

A rotational sensor 136 is mounted with a bracket 138 to the upper framebracket 94 adjacent the upper terminal end of the dancer bar shaft 92.Sensor 136 is coupled with the upper terminal end of the shaft 92 with amagnetic or mechanical coupling 140 and, hence, provides an outputsignal representative of the rotational position of the shaft 92 aboutthe vertical axis 104. As mentioned herein above, the output signal fromthe dancer bar sensor 136 is used to selectively energize the supportingand feeding assembly drive unit 82 and to thereby unwind the plasticfilm roll 38 and advance/deliver additional plastic film web 36 into themachine 10.

In operation, as best seen in FIGS. 9 and 10, the plastic filmlongitudinal edge portions 62L, 62R of the web 36 traverse from the roll38, around the upstream guide roller 112, to and around the downstreamguide roller 122, and then to the opening and closing assembly 24through the perforation and sides seal assembly 20 and the undulatingedge film guiding and supporting assembly 22. The longitudinal edgeportions 62L, 62R hence extend from an upstream location to and aroundthe upstream guide roller 112, to and around the downstream guide roller122 (between guide rollers 112, 122), and then to a downstream location.Accordingly, because the upstream and downstream locations are onopposite sides of the dancer bar assembly 18 and the downstream guideroller 122 is fixed relative thereto while the upstream guide roller ismoveable relative thereto, tension is normally maintained in thelongitudinal portions 62L, 62R as depicted by arrows 142U and 142D. Thatis, because the distance between the guide rollers 112, 122 is fixed bythe roller arm 106, tension in the longitudinal portions 62L, 62R biasesthe dancer bracket 110 in the upstream direction/counterclockwise asviewed from the top and opposite the extension spring 130 bias force inthe clockwise direction as viewed from the top. Additionally, as theplastic film web 36 is pulled into the machine 10, both while the driveunit 82 is not yet energized and when the drive unit 82 is not operatingat a sufficient speed, the tension will increase and thereby cause thedancer bracket 110 to rotate counterclockwise as viewed from the topagainst the bias force of spring 130. Accordingly, as the dancer bracket110 rotates counterclockwise, the web tension is relieved while,simultaneously, rotational position signal is provided by the rotationalsensor 136 which is used to energize and/or change the speed of thedrive unit 82.

Additionally, it has also been found that, because upstream guide roller112 is concave shaped and downstream guide roller 122 is convex shapedand by maintaining tension on the web longitudinal edge portions 62L,62R, the web edge portions 62L, 62R remain horizontally aligned over theguide rollers 112, 122 with the web walls 46L, 46R extending/hangingtherebelow. It has also been found that such horizontal alignment isbest maintained with the upstream movable roller 122 being concaveshaped and the downstream stationary roller 122 being convex shaped.

After the dancer bar assembly 18, the web 36 travels through theperforation and sides seal assembly 20. The perforation and sides sealassembly 20, as shown in FIGS. 12a, 12b, 13a, 13b , 14, 15, 16 a and 16b, is housed in a steel housing 144 mounted to and hanging below themachine frame plate 100. The assembly 20 includes a verticallypositioned heat seal bar 146 adapted to be electrically heated to asufficient and suitable temperature to cut through the web 36 plasticfilm walls 46L, 46R and thereby form the vertical separations 52 and,simultaneously, form the bags fore and aft side seal edges 56F, 56A. Ahorizontally positioned pneumatic cylinder 148 is mounted on theassembly housing 144 and is coupled to the heat seal bar 146 forselectively horizontally withdrawing/retracting the heat seal bar 146,as shown in FIG. 13 a, when the web 36 is traversing through theassembly 20, and for extending the heat seal bar 146, as shown in FIG.13b , at desired spaced distances along the web 36 for thereby for thevertical separations 52 and bags 58. A pair of horizontally positionedslide guide bars 150 are slidingly received through horizontallypositioned cylindrical support members 152 which are mounted on andsupported by the assembly housing 144. Slide guide bar members 150 arecoupled to the heat seal bar 144 vertically above and below thepneumatic cylinder 148 and, as should now be appreciated, support andmaintain the heat seal bar 146 in its vertical orientation while alsoallowing the heat seal bar 146 to be extended and retracted by thepneumatic cylinder 148.

A vertically positioned heat seal backer plate 154 is mounted on theassembly housing 144 adjacent to and spaced from the heat seal bar 146.Accordingly, a plastic film web receiving vertical gap 156 is providedbetween the heat seal bar 146 and the backer plate 154. The plastic filmweb 36 is received through the vertical gap 156 and freely traversestherethrough when the heat seal bar 146 is retracted as shown in FIG.13a . Backer plate 154 includes a backer plate surface 154S whichfunctions as a stop surface for the heat seal bar 146 in a known andcustomary manner. Accordingly, when the pneumatic cylinder 148 drivesthe heat seal bar 146 against the backer plate surface 154S as shown inFIG. 13b , the plastic film web 36 is sandwiched therebetween and theheat from the heat seal bar 146 melts the plastic walls 46L, 46Rtherealong for thereby creating the vertical separation 52 andsimultaneously fusing the resulting edges and forming the bag 58 foreand aft side seal edges 56F, 56A.

To assist in the separation of the side seal edge 56F from the side sealedge 56A and assure that a consistent and complete vertical separation52 is provided between the ago 58, one or more air nozzles 158 areprovided on the assembly housing 144 adjacent to and downstream from theheat seal bar 146 and backer plate 154. See FIGS. 1, 3 and 5-7. Nozzles158 are supplied with pressurized air (not shown) and provide continuousor timed intermittent bursts of air for thereby pushing away and/ordisengaging the formed bag 58 from the upstream plastic film web 36during or immediately after the heat seal bar 146 has been extended ontothe web 36 and backer plate 154.

A perforation knife subassembly 160 is provided vertically above andaligned with the heat seal bar 146 and backer plate 154. Subassembly 160includes a pneumatic cylinder 162, a perforation knife 164 and a web andknife guide block 166. The pneumatic cylinder 162 includes a piston rodattachment block 168 which is rectangular shaped and is slidinglyreceived through a horizontal slot 170 extending through the guide plate172 (not shown in FIG. 15 for clarity) which is attached to the assemblyhousing 144. The attachment block 168 is thereby restrained fromrotating about piston rod and block 168 longitudinal/travel axis 174while being freely movable through the slot 170 by the pneumaticcylinder 160.

A pair of mounting wings 176 are secured to and extend perpendicularlyin opposite directions from the perforation knife 164. The mountingwings 176 are secured to the pneumatic cylinder attachment block 168with fasteners (not shown). Perforation knife 164 is thereby carried onand movable with the attachment block 168 while being restrained fromrotating about the longitudinal/travel axis 174. The perforation knife164 includes a plurality of horizontally projecting vertically alignedneedles 178 having a sharp tip 1180 and a stem 1182. Spaces 184 arethereby formed between the needle stems 182. The perforation knife 164and, hence, the needles are vertically oriented, aligned in the sameplane with the heat seal bar 146 and perpendicular to the web 36travelling through the vertical gap 156.

The guide block 166 includes a vertical web slot 186 extendinghorizontally therethrough in a plane parallel with the web 36. The webslot 186 is defined between an inner surface 1861 and an outer surface1860. The inner surface 1861 is coplanar with the heat seal backer platesurface 154S. An opening 188 at the lower end of the block 166 leads tothe web slot 186. Accordingly, as diagrammatically shown in FIGS. 16a ,16 b, the web longitudinal edge portions 62L, 62R are received throughthe web slot 186 with the web walls 46L, 46R extending therebelowbetween the heat seal bar 146 and the backer plate 154. As should now beappreciated, the vertical gap 156 receiving the web 36 is contiguous andextends along the backer plate surface 154S and the web slot innersurface 186I.

The guide block 166 also includes a vertical knife slot 190 extendinghorizontally therethrough in a plane perpendicular with the web 36.Vertical knife slot 190 is, therefore, also perpendicular to and crossesthe vertical web slot 186. Knife slot 190 is adapted to slidinglyreceive and guide the perforation knife 161 perpendicularly across theweb slot 186, as shown in FIGS. 16a, 16b , so as to thereby perforatethe web 36 and form the perforation lines 66.

In operation, the perforation lines 66 are preferably formedsimultaneously with the vertical separations 52 (FIGS. 13a, 13b ). Asthe web 36 traverses through the perforation and sides seal assembly 20and through the vertical gap 156, the web longitudinal edge portions62L, 62R travel through the web slot 186 and the web walls 46L, 26Rextend therebelow between the heat seal bar 146 and the backer plate154. At desired distances along the web 36 the heat bar pneumaticcylinder 148 and the perforation knife pneumatic cylinder 162 areenergized for extending their respective heat seal bar 146 andperforation knife 164. See FIGS. 13a, 13b and 16a, 16b . The heat sealbar 146, as described hereinabove, creates the vertical separation 52through the web walls 46L, 46R and forms the bag 58 fore and aft sideseal edges 56F, 56A. Simultaneously, the needles 178 of the perforationknife 164 are pushed through the web longitudinal edge portions 62L, 62Ras diagrammatically depicted in FIG. 16b and thereby forming theperforation line 66. It is noted that the width of the needle stems 182and the width of the spaces 184 therebetween affect the resultingrelative strength of the perforation lines 66 and they are adjusted asneeded, depending on the strength of the plastic film web 36, so thatthe tension experienced in the longitudinal edge portions 62L, 62Rbetween the plastic film roll 38 and the bag opening and closingassembly 24 is insufficient to sever the web at the perforations 66,while sufficiently weakening the longitudinal edge portions 62L, 62R tofacilitate detaching the filled bags 58 after the bag opening andclosing assembly 24. After the vertical separation 52 and theperforation line 66 have been formed, the pneumatic cylinders 148 and162 are retracted for withdrawing their respective heat seal bar 146 andperforation knife 164 and so that web 36 can be further advanced asneeded.

As the web 36 travels through the perforation and sides seal assembly 20and while it is between the dancer bar assembly 18 and the bag openingand closing assembly 24, the undulating edge film guiding and supportingassembly 22 functions to maintain the web 36 horizontally aligned and tosupport/carry the bags 58 to the bag opening and closing assembly 24.Undulating edge film guiding and supporting assembly 22 includes a pairof horizontally aligned/coplanar plates 192L, 192R which are secured tothe machine frame plate 100 with vertically extending studs 194L, 194Rand fastener bolts 196. Plates 192L, 192R are thereby spaced from andhang below the machine frame plate 100. Plates 192L, 192R are made ofsteel or other suitably hard material and are relatively thin, i.e.,1/16 inch to ¼ inch, in relation to the web walls 46L, 46R filmthickness which is typically less than 100 mil.

The outside longitudinal edges of plates 192L, 192R are bentperpendicular thereto and form respective longitudinally extendingstiffening ribs 198L, 198R. The inside longitudinal edges 200L, 200R ofplates 192L, 192R have an undulating shape as viewed from the top. Asused herein, “undulating” means a smooth wavelike shape relative to thelongitudinal normal traversing plane along which the plastic film web 36travels from an upstream location to a downstream location and which isdepicted in FIGS. 19, 21 a and 21 b with a long dash line 202. As such,the undulating shaped edges 200L, 200R can be sinusoidal, circular, etc.having peaks and/or valleys displaced relative to the web longitudinalnormal traversing plane 202. That is, having peaks and/or valleysintersecting and/or essentially extending outside/to the side of the weblongitudinal normal traversing plane 202. Preferably, undulating shapededges 200L, 200R are circular shaped peaks and valleys tangentiallyjoined to one another as shown.

Edges 200L, 200R are provided with at least one peak and/or valleyrelative to the web longitudinal normal traversing plane 202, although aplurality of peaks and valleys are preferred. In the most preferredembodiment of machine 10, edges 200L, 200R are provided with four peaksand/or valleys relative to the web longitudinal normal traversing plane202, as shown in FIG. 19, Undulating shaped edges 200L, 200R are mirrorimages of one another and are spaced proximate from each other forthereby forming an undulating gap/travel path 204 therebetween. Thedistance between the edges 200L and 200R and, hence, the width of theundulating gap 204 is sized relative to the thickness of the plasticfilm web 36 so that the web 36 may traverse therethrough preferablysnugly, but certainly freely and without binding. As further describedhereinbelow, the longitudinal edge portions 62L, 62R of the web 36travel through the undulating gap 204 entering at the gap upstreamopening 206 and exiting at the gap downstream opening 208. The upstreamopening 206 and the downstream opening 208 are collinear and are alignedwith the web longitudinal normal traversing plane 202. Althoughflat/planar plates 192L, 192R as shown are preferred, it is contemplatedthat other shaped structures can be used such as, for example, stiffundulating shaped wire, so long as they define undulating proximatemirror image edges 200L, 200R which together form an undulating gap 204.Hence, as used herein, “plates” 192L, 192R is intended to encompass suchother shaped structures.

Referring now more particularly to FIGS. 19, 21 a and 21 b, thelongitudinal edge portions 62L, 62R of the plastic film web 36 are shownas they are received through the undulating gap 204. For clarity, inFIG. 19 the plastic film top free edges 48L, 48R are depicted by theshort dashes line, the normal horizontally straight web longitudinaltraversing plane is depicted by the long dash line 202, and theundulating gap 204 is depicted by a solid line, The normal horizontallystraight web longitudinal traversing plane is also depicted in FIGS. 21aand 21b by a long dashes line 202. As mentioned hereinabove, the dancerbar assembly 18 maintains tension on the web longitudinal edge portions62L, 62R both while the web 36 is traversing through the machine 10 aswell as when the web 36 is stationary. Accordingly, because the plasticfilm forming the web 36 is flexible, the tension causes the longitudinaledge portions 62L, 62R to be forced perpendicularly against theundulating shaped edges 200L, 200R at the edge peaks relative to the weblongitudinal normal traversing plane 202. That is, because the appliedtension in the web longitudinal edge portions 62L, 62R is aligned withthe web longitudinal normal traversing plane 202, the web longitudinaledge portions 62L, 62R are biased/urged towards the longitudinal normaltraversing plane 202. As a result thereof, the web longitudinal edgeportions 62L, 62R tend to fold/bend over the undulating shaped edges2001, 200R at the edge peaks relative to the web longitudinal normaltraversing plane 202. For example, as depicted in FIG. 21a , the peakedge 200L at cross-section 21 a of FIG. 19 causes the longitudinal edgeportions 62L, 62R to fold/bend thereover toward the longitudinal normaltraversing plane 202 and towards the left aligned plate 192L. However,as depicted in FIG. 22b , the peak edge 200R at cross-section 21 b ofFIG. 19 causes the longitudinal edge portions 62L, 62R to fold/bendthereover toward the longitudinal normal traversing plane 202 andtowards the right aligned plate 192R. As should now be appreciated, thefolds/bends over the plate undulating edges 200L, 200R causes thetensioned web 36 to align with and vertically “grip” the undulatingplates edges 200L, 200R and, accordingly, carry the plastic film bags 58extending therebelow.

As should now further be appreciated, the folds/bends causing thetensioned web 36 to align with and vertically “grip” the undulatingplates edges 200L, 200R occur at the peaks of the undulating edges 200L,200R which are displaced relative to/which extend out of the weblongitudinal normal traversing plane 202. Accordingly, the valleyportions of the plates 192L, 192R can be eliminated. That is, the valleyportions 192L-V and 192R-V depicted by cross-hatching in FIG. 19a can beremoved from the respective plates 192L, 192R thereby resulting inplates 192L-V-N and 192R-V-N shaped as shown in FIG. 19b wherein theresulting plates are shown separated from one another for clarity.Alternatively, as shown in the embodiment of FIG. 19 c, the valleyportions can be completely eliminated thereby resulting in four separateconsecutively spaced longitudinally aligned plates 192R-1, 192L-2,192R-3 and 192L-4. Plates 192R-1 and 192R-3 are secured to the machineframe plate 100 with separate vertically extending studs 194R, andplates 192L-2 and 192L-4 are secured to the machine frame plate 100 withseparate vertically extending studs 194L.

In both embodiments of FIGS. 19a-19b and 19 c, consecutively spacedlongitudinally aligned peak edges 192R-1-P, 192L-2-P, 192R-3-P and192L-4-P are provided which are displaced relative to/which extend outof the web longitudinal normal traversing plane 202. In the embodimentof FIGS. 19a -19 b, plates 192L-V-N and 192R-V-N are coplanar and extendthrough the web longitudinal normal traversing plane 202, In theembodiment of FIG. 19c , all the plates 192R-1, 192L-2, 192R-3 and192L-4 are coplanar with each other and similarly extend through the weblongitudinal normal traversing plane 202. Accordingly, all the peakedges 192R-1-P, 192L-2-P, 192R-3-P and 192L-4-P are coplanar and,preferably, are in a plane perpendicular to the web 36 longitudinalnormal traversing plane 202. Also, traveling/extending along the weblongitudinal normal traversing plane, the odd peak edges 192R-1-P and192R-3-P are displaced/extend out of the web longitudinal normaltraversing plane 202 in a direction opposite the direction that the evenpeak edges 192L-2-P and 192L-4-P are displaced/extend out of the weblongitudinal normal traversing plane 202. In the embodiment of FIGS. 19a-19 b, the odd peak edges 192R-1-P and 192-3-P are provided on plate192R-V-N and the even peak edges 192L-2-P and 102L-4-P are provided onplate 192L-V-N. the embodiment of FIG. 19c , the peak edge 192R-1-P isprovided on plate 192R-1, the peak edge 192L-2-P is provided on plate192L-2, the peak edge 192R-3-P is provided on plate 192R-3 and the peakedge 192L-4-P is provide on plate 192L-4. Accordingly, although a “gap”204 is not provided in the embodiments of FIGS. 19a-19b and 19 c, thepeak edges 192R-1-P, 1921,2-P, 192R-3-P and 192L-4-P create a similarlyshaped, essentially continuous, undulating plastic film travel path 204Palong the web longitudinal normal traversing plane 202, and so theseembodiments function essentially the same as the embodiment of FIG. 19as described hereinabove.

Through experimentation it has further been found that the plates 192L,192R need not be coplanar and, in fact, function equally as well, if notbetter, when they are located in parallel planes to one another and arevertically offset as depicted in FIGS. 21c and 21 d. The undulatingedges 200L, 200R are thereby located in planes parallel to one anotherand are vertically offset and proximate to one another thereby formingan undulating gap/travel path 204 therebetween. The undulating edges200L, 200R here are preferably vertically aligned as shown. It is notedalso that the undulating edges 200L, 200R can also be both verticallyand horizontally offset/spaced from one another. The horizontal offsetdistance between the undulating edges 200L, 200R in FIGS. 21a, 21b andthe vertical offset distance between the undulating edges 200L, 200R inFIGS. 21c, 21d , as will be appreciated to one skilled in the art, areadjusted depending on the thickness and flexibility of the plastic filmweb 36.

There are times when tension in the web 36 cannot be provided and/or isnot desired such as when machine 10 is being serviced and when theplastic film web 36 is initially being threaded therethrough. In thisregard, as shown in FIGS. 17, 18 a and 18 b, clamp members 210 areprovided on the upper surface of the aligned plates 1921, 192R forselectively gripping and holding the web 36 thereat. Clamp members 210include spring plungers 212 threadingly coupled on brackets 214 whichare secured to plate 192R. Rubber bumpers 216 are provided adjacent toand opposing the spring plungers 212 with brackets 218 which are securedto plate 192L. The spring plungers 212 are therefore selectivelyextendable and retractable as shown in FIGS. 18a and 18b for therebyselectively sandwiching/clamping the web longitudinal edge portions 62L,62R and selectively retaining the web 36 thereat as shown until the webis tensioned.

As mentioned hereinabove, after traversing through the undulating edgefilm guiding and supporting assembly 22, the web 36, which waspreviously formed into bags 58 linked by the longitudinal edge portions62L, 62R, travels to the bag opening and closing assembly 24 whereat thelongitudinal edge portions 62L, 62R are separated for opening andfilling the bags 58 and are then brought back together/adjacent oneanother and closing the bags 58. The bag opening and closing assembly24, as more particularly shown in FIGS. 22-26, includes a pair ofopposing horizontally sliding gates 220L, 220R located below andsupported by the frame plate 100. As shown in FIGS. 24a-24d and 25a -25c, the gates 220L, 220R travel in a horizontal plane and open and closein a direction perpendicular to the web towards and away from the normalhorizontally straight web traversing plane (depicted by the long dashline 202 only in FIG. 24d for clarity). A duct 222 located above andalso supported by the frame plate 100 is adapted to be connected to thebulk material feeding apparatus chute 14 and leads to the top of gates220L, 220R. As mentioned hereinabove, after a bag 58 is opened, ameasured quantity of bulk material 68 is delivered/dropped through thechute 14 and duct 222, through the open gates 220L, 220R and into thebag. After the measured quantity of bulk material 68 isdelivered/dropped into the bag 58, the gates close and release the weblongitudinal edge portions 62L, 62R for delivering the bag to the bagpulling and sealing assembly 26.

An upstream crossbeam 224U and a downstream crossbeam 224D are fixed tothe underside of the frame plate 100 and extend vertically downwardlytherefrom and perpendicular to the web normal traversing plane 202.Crossbeams 224U, 224D each include a notch 226 which open downwardly andthrough which the web longitudinal edge portions 62L, 62R are received.Longitudinal crossbeams 227L, 227R are similarly fixed to the undersideof the frame plate 100 and extend vertically downwardly therefrom.Longitudinal crossbeams 227L, 227R, however, are parallel to the weblongitudinal edge portions 62L, 62R and extend between and perpendicularto the upstream and downstream crossbeams 224U, 224D.

Sliding gates 220L, 220R include respective gate plates 228L, 228Rextending between the upstream and downstream crossbeams 224U, 224D.Upper and lower gate bearings 230U, 230L are rotatably secured to theupstream and downstream crossbeams 224U, 224D. Gate plates 228L, 228Rare positioned between the upper and lower gate bearings 230U, 230L andare thereby slidingly supported on the upstream and downstreamcrossbeams 224U, 224D. Gate plates 228L, 228R are, thus, movableperpendicularly towards and away from the web normal traversing plane202. Leading gate closure and film guide plates 232L, 232R are securedto the gate plates 228L, 228R and extend perpendicularly downwardtherefrom along the gate plates 228L, 228R inner edge As best seen inFIGS. 22 and 24 a-24 d, gate closure and film guide plates 232L, 232Rare shorter than the width of the gate plates 228L, 228R and, hence,stop short of and define a gap between the gate closure and film guideplates 232L, 232R and each of the upstream and downstream crossbeams224U, 224D. As best seen in FIGS. 22, 24 a, 25 a and 26, when the gates220L, 220R are in their closed position the gate closure and film guideplates 232L, 232R are adjacent to and in contact with each other.Pneumatic cylinders 234L, 234R are secured to the respectivelongitudinal crossbeams 227L, 227 and are pivotally coupled at aweldment 236L, 236R to a respective gate plate 228L, 228R. The gateplates 228L, 228R are thereby selectively movable towards and away fromthe web normal traversing plane 202 as shown in FIGS. 24a-24d and 25a-25 c.

The sliding gates 220L, 220R each include a respective clamp bar 238L,238R slidingly mounted on a respective gate plate 228L, 228R and,together with a respective gate closure and film guide plate 232L, 232R,forming a clamp/gripper having a respective longitudinal channel 240L,240R wherethrough the respective web longitudinal edge portions 62L, 62Rare received (FIGS. 25a-25c and 26). Clamp bars 238L, 238R are mountedand carried on the gate plates 228L, 228R with a pair of rods 242extending perpendicular to the gate closure and film guide plates 232L,232R. Rods 242 are secured to the damp bars 238L, 238R and slidinglyextend through a weldment 244 secured to the gate plates 228L, 228R anda respective hole through a longitudinal cross beam 227L, 227R, Theterminal end of the rods 242 opposite their attachment to the clamp bars238L, 238R are provided with stops 246, preferably in the form of awasher and shoulder bolt threadingly secured thereto. Compressionsprings 248 are provided between the weldments 244 and the clamp bars238L, 238R circumferentially around the rods 242. Accordingly, thecompression springs 248 urge/bias the clamp bars 238L, 238R away fromthe weldments 244 and towards the gate closure and film guide plates232L, 232R. As best seen in FIGS. 24a-24d and 26, the clamp bars 238L,238R are about the same length as the gate closure and film guide plates232L, 232R and include a rubber longitudinal strip 250 along theirleading gripping/clamping face adjacent to the gate closure and filmguide plates 232L, 232R.

Importantly, the overall length of the rods 242 and width of theirrespective clamp bars 238L, 238R (from the rubber longitudinal strip 250at the clamp bars gripping/clamping face to the rod stops 246) isshorter than the distance between the gate closure and film guide plates232L, 232R and their respective longitudinal crossbeams 227L, 227R whenthe gates 220L, 220R are in their closed positions as seen in FIGS. 22,24 a, 25 a and 26. Accordingly, when the gates 220L, 220R are closed,the pneumatic cylinders 234L, 234R push their respective gate plates228L, 228R and gate closure and film guide plates 232L, 232R against theforce of the compression springs 248 placing the rods 242 in tension andthereby separating the gate closure and film guide plates 232L, 232Rfrom their respective adjacent clamp bars 238L, 238R and thereby formingrespective longitudinal film receiving channels 240L, 240R therebetweenfor receipt of the web longitudinal edge portions 62L, 62R. However, asthe gates 220L, 220R are opened and while they are in their openposition as shown in FIGS. 24b-24d and 2 5b-25 c, the tension in therods 242 is released and the springs 248 push the clamp bars 238L, 238Rtowards their respective gate closure and film guide plates 232L, 232Rthereby forcing the rubber longitudinal strips 250 against the gateclosure and film guide plates 232L, 232R and clamping/gripping the weblongitudinal edge portions 62L, 62R therebetween.

The bag opening and closing assembly 24 further includes a pair ofupstream opposing rubber rollers 252L, 252R carried on the upstreamcrossbar 224U and adapted to receive and guide the web longitudinal edgeportions 62L, 62R therebetween. Pneumatic cylinders 254, also carried onthe upstream crossbar 224U, are coupled to the rollers 252L, 152R andare adapted to selectively: extend and firmly compress the rollers 252L,252R against each other at a high pressure to prevent rotation thereofand thereby pinch/clamp the web longitudinal edge portions 62L, 62Rtherebetween and prevent longitudinal movement thereof (rollers “clampedposition”); extend and compress the rollers 252L, 252R against eachother at a low pressure and allowing rotation thereof to thereby lightlygrip and allow movement of the web and to thereby guide the weblongitudinal edge portions 62L, 62R traversing therebetween (rollers“guiding position”); and, relax and/or retract the rollers 252L, 252R tothereby freely allow movement of the web longitudinal edge portions 62L,62R therethough (rollers “released position”).

Similarly, a pair of downstream opposing rubber rollers 256L, 256R arecarried on the downstream crossbar 224D and are adapted to receive andguide the web longitudinal edge portions 62L, 62R therebetween.Pneumatic cylinders 254, also carried on the downstream crossbar 224D,are coupled to the rollers 256L, 156R and are adapted to selectively:extend and firmly compress the rollers 256L, 256R against each other ata high pressure to prevent rotation thereof and thereby pinch/clamp theweb longitudinal edge portions 62L, 62R therebetween and preventlongitudinal movement thereof (rollers “clamped position”); extend andcompress the rollers 256L, 256R against each other at a low pressure andallowing rotation thereof to thereby lightly grip and allow movement ofthe web and to thereby guide the web longitudinal edge portions 62L, 62Rtraversing therebetween (rollers “guiding position”); and, relax and/orretract the rollers 256L, 256R away from each other to thereby freelyallow movement of the web longitudinal edge portions 62L, 62Rtherethough (rollers “released position”).

Referring now more particularly to FIGS. 24a-24d and 25a -25 c, inoperation, when the gates 220L, 220R are in their closed position asshown in FIGS. 24a and 25a , the longitudinal film receiving cha 240L,240R are open and the upstream opposing rollers 252L, 252R and thedownstream opposing rollers 256L, 256R are in their released positionsfor thereby allowing the web longitudinal edge portions 62L, 62R tofreely traverse therethrough. When a bag 58 has advanced under the bagopening and closing assembly 24, the gates pneumatic cylinders 234L,234R are retracted while the upstream opposing rollers 252L, 252R andthe downstream opposing rollers 256L, 256R are placed in their guidingpositions as shown in FIG. 24b . As the gates 220L, 220R begin to open,as shown in FIGS. 24b and 25b , the clamp bars 238L, 238R are pushedagainst their respective gate closure and film guide plates 232L, 232Rthereby closing the film receiving channels 240L, 240R and firmlygripping the web longitudinal edge portions 62L, 62R therebetween. Withthe upstream opposing rollers 252L, 252R and the downstream opposingrollers 256L, 256R in their guiding positions, the gates 220L, 220R arefully opened while, simultaneously, pulling the web longitudinal edgeportions 62L, 62R through both the upstream opposing rollers 252L, 252Rand the downstream opposing rollers 256L, 256R into the opening andclosing assembly 24 and between the upstream and downstream crossbeams224U, 224D.

When the gates have reached their fully open position as shown in FIGS.24c and 25c , the upstream opposing rollers 252L, 252R and thedownstream opposing rollers 256L, 256R are placed in their clampedpositions thereby pinching and preventing longitudinal movement of theweb longitudinal edge portions 62L, 62R both upstream and downstream ofthe opening and closing assembly 24. A pre-measured quantity of bulkmaterial 68 is then released through the chute 14 dropping through thegates 220L, 220R and into the bag 58 as shown in FIG. 5. After the bag58 has been loaded with the bulk material 68, the upstream opposingrollers 252L, 252R and the downstream opposing rollers 256L, 256R areagain placed in their guiding positions as shown in FIG. 24d . The gatespneumatic cylinders 234L, 234R are extended thereby closing the gates220L, 220R as shown in FIGS. 24a and 25a whereat the web longitudinaledge portions 62L, 62R are again free to traverse therethrough. It isnoted that, while the gates 220L, 220R are closing, the slack created inthe upstream web longitudinal edge portions 62L, 62R is pulled out ofthe assembly 24 through the upstream opposing rollers 252L, 252R by thedancer bar assembly 18. The slack created in the downstream weblongitudinal edge portions 62L, 62R is pulled out of the assembly 24through the downstream opposing rollers 256L, 256R by the bag pullingand sealing assembly 26 as described herein below.

The bag pulling and sealing assembly 26 includes a heat sealingsubassembly 258 for heat sealing/fusing the bag film walls 46L, 46R toone another between the fore and aft side seal edges 56A, 56F and agripping and pulling subassembly 260 for pulling the web longitudinaledge portions 62L, 62R into the heat sealing subassembly 258. After thebag 58 has been filled, closed and the web longitudinal edge portions62L, 62R released, the vertically moving and horizontally conveyingassembly 28 conveys it to the bag pulling and sealing assembly 26 while,simultaneously, the pulling and gripping subassembly 260 grips and pullsthe web longitudinal edge portions 62L, 62R into the heat sealingsubassembly 258.

The bag heat sealing subassembly 258 includes a pair of elongatehorizontally disposed heat seal bars 262L, 262R extending parallel withthe web 36 and adapted to travel in a horizontal plane, opening andclosing in a direction perpendicular to the web 36 toward and away fromthe normal horizontally straight web traversing plane (depicted by thelong dash line 202 in FIG. 30). Heat seal bars 262L, 262R includerespective longitudinal leading contact faces 263L, 263R and are adaptedto be electrically heated to a sufficient and suitable temperature tomelt/fuse the plastic film bag walls 46L, 46R together and thereby sealthe bags 58 closed.

The heat seal bars 262L, 262R are carried on a respective carrying block266L, 266R. A pair of horizontally positioned pneumatic cylinders 264L,264R are mounted on the heat seal assembly housing 265 (FIGS. 5, 6, 31 aand 31 b) secured to the machine horizontal upper beams 34L, 34R.Pneumatic cylinders 264L, 264R are coupled to a respective carryingblock 266L, 266R for thereby selectively horizontally extending andretracting the carrying Hocks 2661, 266R and their respective heat sealbars 262L, 262R as shown in FIGS. 31a and 31 b.

A pair of horizontally positioned slide guide bars 268L, 268R areslidingly received through respective horizontally positionedcylindrical support members 270L, 270R. The cylindrical support members270L, 270R include flanges 267 and are, thereby, mounted on the heatseal assembly housing 265. The pair of slide guide bars 268L are coupledto the carrying block 266L longitudinally upstream and downstream fromthe pneumatic cylinder 264L. Similarly the pair of slide guide bars 268Rare coupled to the carrying block 266R longitudinally upstream anddownstream from the pneumatic cylinder 264R. Accordingly, the carryingblocks 266L, 266R and the heat seal bars 262L, 262R thereon aremaintained in their horizontal orientation while also being extendableand retractable by their respective pneumatic cylinder 264L, 264R asshown in FIGS. 31 a, and 31 b.

Horizontally disposed clamp bars 272L, 272R are mounted on respectivecarrying blocks 266L, 266R vertically below and parallel with respectiveheat seal bars 262L, 262R and the web 36 normal traversing plane 202, Asbest seen in FIGS. 31a and 31b , clamp bars 272L, 272R are each mountedon their respective carrying block 2661, 266R with shoulder bolts 274which extend through a hole (not shown) and a countersunk bore 276 andwhich are threadingly secured to the clamp bar 272L, 272R. A compressionspring 278 is received in the countersunk bore 276 circumscribing theshoulder bolt 274. The springs 278 extend between the bottom of thecountersunk bores 276 and the clamp bars 272L, 272R therebypushing/biasing the clamp bars 272F, 272R horizontally away from theirrespective carrying block 266L, 266R and towards the web 36 normaltraversing plane 202. The length of the shoulder bolts 274 is greaterthan the width of the carrying block 266L, 266R so that the clamp bars272L, 272R are normally pushed/biased by the springs 278 a distance awaytherefrom as shown in FIG. 31a , and are movable toward their respectivecarrying block 266L, 266R against the force of the springs 278 as shownin FIG. 31b . Clamp bars 272L, 272R include respective leadinghorizontal and longitudinally disposed contact faces 280L, 280R. Rubberstrips 282 extend longitudinally along the clamp bar faces 280L, 280Rfor frictionally engaging the bag plastic film walls 46L, 46R.

As should now be appreciated and shown in FIGS. 29, 30 and 31 a, whenthe pneumatic cylinders 264L, 264R are retracted, a longitudinallyextending gap 284 is provided between the heat seal bar 262L and clampbar 272L on one side and the heat seal bar 262R and clamp bar 272R onthe other side wherethrough the bag walls 46L, 46R are received, Also,as best seen in FIG. 31a , when the pneumatic cylinders 264L, 264R areretracted, the clamp bars 272L, 272R are pushed/biased by the springs278 away from their respective carrying block 266L, 266R a distancesufficient for locating the clamp bar faces 280L, 280R beyond the heatseal bar contact faces 263L, 263R into the gap 284 and closer to the web36 and plastic film bag walls 46L, 46R.

After a bag 58 is conveyed under the heat sealing subassembly 258 andthe plastic film walls 46L, 46R thereof are received in the gap 284 asshown in FIG. 31a , the pneumatic cylinders 264L, 264R are actuatedthereby extending their respective heat seal bars 262L, 262R and clampbars 272L, 272R closing the gap 284 and clamping the bag walls 46L, 46Rtherebetween as shown in FIG. 31a . It is noted that, because the clampbar faces 280L, 280R extend beyond the heat seal bar contact faces 263L,263R into the gap 284, when the pneumatic cylinders 264L, 264R areextended, the clamp bar faces 280L, 280R first contact the respectivebag walls 46L, 46R whereby the bag walls 46L, 46R are first frictionallyengaged between the respective rubber strips 282 of the clamp bar faces280L, 280R. As the carrying blocks 266L, 266R are pushed further towardeach other and travel closer toward the web normal longitudinal normaltraversing plane 202, the clamp bars 272L, 272R are pushed against thesprings 278 and move toward their respective carrying blocks 266L, 266Ras shown in FIG. 31b and the heat seal bar contact faces 263L, 263R thensandwich and contact the bag film walls 46L, 46R thereby melting/fusingthem to one another and thereby sealing the bags 58 closed between thebag fore and aft side sealed edges 56F, 56A. After the walls 46L, 46Rhave been sealed closed, the pneumatic cylinders 264L, 264R areretracted thereby pulling their respective heat seal bars 262L, 262R andclamp bars 272L, 272R away therefrom as shown in FIG. 31a , and thefilled and heat sealed closed bag 58 is conveyed away from under theheat sealing subassembly 258 by the vertically moving and horizontallyconveying assembly 28.

The gripping and pulling subassembly 260 includes a drive belt unit 286mounted on the end tube member 30L and rotatably driving the drivetoothed belt pulleys 288L, 288R. Drive pulleys 288L, 288R are coupledwith respective driven toothed belt pulleys 290L, 290R with respectivetoothed belts 292L, 292R. The driven pulleys 290L, 290R are rotatablysupported on the machine upper beams 34L, 34R and are located. adjacentthe bag opening and closing assembly 24. As best seen in FIGS. 27 and28, toothed belts 292L, 292R extend horizontally longitudinally parallelwith the web 36 longitudinal normal traversing plane 202 and are locatedabove the heat sealing subassembly 258. Toothed belt 292L is located onone side of the web 36 longitudinal normal traversing plane 202 andgenerally over the heat sealing subassembly carrying block 266L and heatseal bar 262L whereas toothed belt 292R is located on the other side ofthe web 36 longitudinal normal traversing plane 202 and generally overthe heat sealing subassembly carrying block 266R and heat seal bar 262R.

A carriage 294 extends horizontally perpendicular to the web 36longitudinal normal traversing plane 202 and between the toothed belts292L and 292R. Carriage 294 is clamped onto and is secured to thetoothed belts 292L, 292R and is thereby adapted to travel longitudinallyalong the web 36 normal traversing plane 202 between the drive pulleys288L, 288R and the driven pulleys 290L, 290R. Preferably, carriage 294is secured to the lower longitudinally extending bands of the toothedbelts 292L, 292R thereby placing it vertically closer to the heatsealing subassembly 258.

A pair of gripping fingers 296L, 296R are coupled to respectivepneumatic cylinders 298L, 298R which are, in turn, mounted on andcarried by the carriage 294. Gripping fingers 296L, 296R are therebyalso carried on and travel with the carriage 294 between the drivepulleys 288L, 288R and the driven pulleys 290L, 290R, while also beingselectively movable toward and away from the web 36 longitudinal normaltraversing plane 202 for thereby selectively clampingtherebetween/gripping the longitudinal edge portions 62L, 62R of the web36. Gripping fingers 296L, 296R and pneumatic cylinders 298L, 298R aresometimes collectively referred to herein as a “gripper” 296. Grippingfingers 296L, 296R include respective gripping faces 300L, 300R opposingeach other and forming a web receiving gap 302 therebetween when thepneumatic cylinders 298L, 298R are retracted. Gripping finger faces300L, 300R are each provided with a rear raised contact face 304 andforward raised gripping ribs 306. As best seen in FIG. 34b , whenpneumatic cylinders 298L, 298R are extended pushing the gripping fingers296L, 296R toward the web 36 longitudinal normal traversing plane 202and against each other, the rear raised contact faces 304 come incontact with each other and the forward raised gripping ribs 306 conicin contact with each other thereby providing a relief gap 308therebetween. As should be appreciated, the raised contact faces 304 andgripping ribs 306 relative to the relief gap 308 therebetween assuresthat the clamping force between the gripping fingers 296L, 296R isapplied at the raised ribs 306 for thereby better clamping/gripping thebag longitudinal edge portions 62L, 62R.

In operation, during or after the bags 58 have been opened and filledwith bulk material 68 and while the downstream opposing rollers 256L,256R are compressed and prevent longitudinal movement of the weblongitudinal edge portions 62L, 62R, the toothed belts 292L, 292R aredriven for thereby moving the gripping fingers 296L, 296R adjacent thebag opening and closing assembly 24 whereat the web longitudinal edgeportions 62L, 62R of the bag under the bag opening and closing assembly24 extend partially downstream beyond the downstream opposing rollers256L, 256R. The web longitudinal edge portions 62L, 62R extendingpartially beyond the rollers 256L, 256R is thereby received in the webreceiving gap 302 between the gripping fingers 296L, 296R. Pneumaticcylinders 298L, 298R are then extended moving the gripping fingerstoward the web 36 longitudinal normal traversing plane 202 and againsteach other thereby clamping/gripping the web longitudinal edge portions62L, 62R between the gripping finger forward raised gripping ribs 306.The gripping fingers 296L, 296R are then advanced downstream towards theheat sealing subassembly 258 as the filled bag 58 under the opening andclosing assembly 24 is closed and another bag 58 is delivered thereunderand again opened. At that point, as the next bag is being opened, theclamp bars 238L, 238R are again pushed against their respective gateclosure and film guide plates 232L, 232R thereby closing the filmreceiving channels 240L, 240R and firmly gripping the web longitudinaledge portions 62L, 62R therebetween and thereby stopping furtheradvancement of the web 36 beyond the opening and closing assembly 24.See FIGS. 24a-24d and 25a -25 c. Further downstream advancement of thegripping fingers 296L, 296R then causes the longitudinal edge portions62L, 62R of the filled bag 58 to be severed from the longitudinalportions 62L, 62R of the bag now under the opening and closing assembly24 at the perforation line 66 therebetween. After the longitudinal edgeportions 62L, 62R of the filled bag have been advanced to within theheat sealing subassembly 258, the pneumatic cylinders 298L, 298R andgripping fingers 296L, 296R are retracted thereby releasing thelongitudinal edge portions 62L, 62R therebetween, Gripping fingers 296L,296R are then again moved upstream adjacent the opening and closingassembly 24 and their process of operation is repeated.

As mentioned hereinabove, the vertically moving and horizontallyconveying assembly 28 cooperates with the opening and closing assembly24 and the pulling and sealing assembly 26 and functions to verticallysupport and move and horizontally convey the bags while they are beingfilled, closed, heat sealed closed and, finally, removed from themachine 10. As best seen in FIGS. 27 and 28, assembly 28 includes aconveyor 310 securely mounted to and carried on vertical posts 312R,312L and extending horizontally longitudinally parallel with the web 36longitudinal normal traversing plane 202 under the bag opening andclosing assembly 24 and the bag pulling and sealing assembly 28. A driveunit 314 is coupled to and selectively drives the conveyor 310. Conveyor310 is provided for and is adapted to carry and convey the bags 58 thathave been filled with bulk material 68 as described herein.

Vertical posts 312R, 312L are slidingly received through couplings 316which are secured to the machine horizontal lower beams 32L, 32R andupper beams 34L, 34R and are thereby all vertically movabletherethrough. A bag guide bar 319L is secured to the vertical posts 312Land extends horizontally longitudinally parallel and on one side of theweb 36 longitudinal normal traversing plane 202. Similarly, a bag guidebar 319R is secured to the vertical posts 312R and extends horizontallylongitudinally parallel and on the other side of the web 36 longitudinalnormal traversing plane 202. Vertical posts 312R, 312L are joined to oneanother with a horizontal plate 318. A pneumatic cylinder 320 is securedto the machine lower beams 32L, 32R and is coupled to the horizontalplate 318. Accordingly, by extending and retracting pneumatic cylinder320, the horizontal plate 318 and vertical posts 312L, 312R along withthe conveyor 310 and bag guide bars 319L, 319R are movable in unisonvertically up and down as indicated by arrow 322.

The operation of the vertically moving and horizontally conveyingassembly 28 is depicted in FIGS. 35a-35d whereat consecutive bags 58being formed and filled are diagrammatically shown and depicted by thenumerals 58 a-58 e. In FIG. 35a , the conveyer 310 is shown in its lowerposition after a filled bag 58 a has been heat sealed by the heatsealing subassembly 258 along a heat seal/closure line 324 in the bagwalls 46L, 46R at or adjacent to the longitudinal edge portions 62L, 62Rthereof and extending between the bag fore and aft sealed edges 56F,56A. As also depicted in FIG. 35a , the next bag 58 b has already beenreceived, opened and is ready to be filled at the opening and closingassembly 24. Furthermore, the longitudinal edge portions 62L, 62R arerestrained, both upstream and downstream, by the pinch rollers 252L,252R and 256L, 256R, and the gripper 296 has been advanced adjacent theopening and closing assembly 24 and has gripped the longitudinal edgeportions 621, 62R of the next bag 58 b.

With the conveyor 310 still in its lower position, the filled bag 58 ais conveyed out of the machine 10 and bulk material 68 is dropped intothe bag 58 b, as diagrammatically depicted in FIG. 5, through the bagopening and closing assembly 24.

Thereafter, simultaneously: the pinch rollers 252L, 252R and 256L, 256Rare relaxed thereby freeing the longitudinal edge portions 62L, 62R formovement; the conveyor 310 is moved upwardly as shown in FIG. 35b ; thebag opening and closing assembly closes the bag 58 b; and, the gripper296 pulls the longitudinal edge portions 62L, 62R toward the heatsealing subassembly 258 as shown in FIG. 35b . As should be appreciated,the slack created in the longitudinal edge portions 62L, 62R by theclosing of the opening and closing assembly sliding gates 220L, 220R istaken up by the gripper 296 and the upstream dancer bar assembly 18.Additionally, needed slack is provided in the bag walls 46L, 46R abovethe fill level of bulk material 68 by the conveyor 310 moving upwardly.

The filled bag 58 b and web 36 upstream therefrom is then conveyedfurther downstream, as shown in FIG. 35c , whereat the next bag 58 c hasadvanced under the opening and closing assembly 24 and bag 58 b hasadvanced under the heat sealing subassembly 258. Here, bag 58 c is nowopened and the pinch rollers 252L, 252R and 256L, 256R are againcompressed thereby again restraining the longitudinal edge portions 62L,62R both upstream and downstream. Simultaneously, as the bag 58 b isconveyed, gripper 296 pulls the longitudinal edge portions 62L, 62R intothe heat sealing subassembly 258.

Next, bag 58 b is conveyed further downstream and, simultaneously, thelongitudinal edge portions 621, 62R are pulled fully into the heatsealing subassembly 258 thereby also severing the longitudinal edgeportions 62L, 62R of the bag 58 b from the longitudinal edge portions62L, 62R of bag 58 c at the perforation line 66. The heat sealingassembly 258 then heat seals/fuses closed the bag walls 46L, 46R of bag58 b as described hereinabove along a heat seal/closure line 324, andthe process is repeated.

While this invention has been described as having an exemplary design,the present invention may be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the invention using itsgeneral principles.

What is claimed is:
 1. A apparatus for opening and filling verticallypositioned plastic film bags traversing horizontally along a normaltraversing plane from an upstream location to a downstream locationwherein said bags include a pair of parallel proximate longitudinal edgeportions defining a bag opening therebetween leading to a bag cavityvertically therebelow, said apparatus comprising: a first gate on oneside of said normal traversing plane selectively moveable between aclosed position adjacent said normal traversing plane and an openposition at a distance away from said normal traversing plane; a secondgate on the other side of said normal traversing plane opposing saidfirst gate and selectively moveable between a closed position adjacentsaid normal traversing plane and an open position at a distance awayfrom said normal traversing plane; wherein each said first and secondgates include a longitudinal channel receiving one of said baglongitudinal edge portions therethough; wherein said longitudinalchannels allow said bag edge portions to traverse therethrough when saidgates are in their closed position and clampingly grip said bag edgeportions when said gates are away from their closed position; and,wherein, when said gates are in their open positions, said baglongitudinal portions are gripped and separated from one another forthereby opening and filling the bag and, when said gates are in theirclosed positions, said bag longitudinal portions are released andallowed to longitudinally traverse through their respective longitudinalchannel.
 2. The apparatus of claim 1 wherein each said longitudinalchannel is formed between a leading gate plate and a selectivelymoveable clamp bar, said clamp bar being moveable away from said leadinggate plate when said gate is in its closed position thereby opening saidlongitudinal channel and allowing said bag edge portion to traversetherethrough, and being moveable against said leading gate plate whensaid gate is away from its closed position thereby closing saidlongitudinal channel and clampingly griping said bag edge portiontherebetween.
 3. The apparatus of claim 2 wherein one or more springsmove said clamp bar against said leading gate plate when said gate isaway from its closed position.
 4. The apparatus of claim 3 wherein apneumatic cylinder is coupled to each of said first and second gates andwherein said pneumatic cylinders are selectively actuable for movingsaid gates to their closed and open positions.
 5. The apparatus of claim1 wherein, while said gates are being moved from their closed positionsto their open positions, additional longitudinal edge portions arepulled into the apparatus from at least one of said upstream anddownstream locations and, while said gates are being moved from theiropen positions to their closed positions, said additional longitudinaledge portions are pulled out of said apparatus towards at least one ofsaid upstream and downstream locations.
 6. The apparatus of claim 5wherein a dancer bar assembly is provided at said upstream location andprovides tension is said longitudinal edge portions and pulls saidadditional edge portions out of said apparatus while said gates arebeing closed.
 7. The apparatus of claim 5 wherein a gripping and pullingassembly is provided at said downstream location and pulls saidadditional edge portions out of said apparatus while said gates arebeing closed.
 8. The apparatus of claim 5 wherein said additionallongitudinal portions at said upstream location extend through a pair ofupstream clamping members and said additional longitudinal portions atsaid downstream location extend through a pair of downstream clampingmembers and wherein, while said gates are in their closed positions,said upstream and downstream clamping members allow said additionallongitudinal portions to traverse therethrough and, while said gates arein their open positions, said upstream and downstream clamping membersclampingly grip and prevent said additional longitudinal portions otraverse therethrough.
 9. The apparatus of claim 8 wherein said clampingmembers are rubber rollers and wherein, while said gates are opening andclosing, said rollers guide said additional longitudinal edges as theytraverse therethrough.
 10. The apparatus of claim 5 wherein each saidlongitudinal channel is formed between a leading gate plate and aselectively moveable clamp bar, said clamp bar being moveable away fromsaid leading gate plate when said gate is in its closed position therebyopening said longitudinal channel and allowing said bag edge portion totraverse therethrough, and being moveable against said leading gateplate when said gate is away from its closed position thereby closingsaid longitudinal channel and clampingly griping said bag edge portiontherebetween.
 11. The apparatus of claim 10 wherein one or more springsmove said clamp bar against said leading gate plate when said gate isaway from its closed position.
 12. The apparatus of claim 11 wherein apneumatic cylinder is coupled to each of said first and second gates andwherein said pneumatic cylinders are selectively actuable for movingsaid gates to their closed and open positions.
 13. The apparatus ofclaim 10 wherein a dancer bar assembly is provided at said upstreamlocation and provides tension is said longitudinal edge portions andpulls said additional edge portions out of said apparatus while saidgates are being closed.
 14. The apparatus of claim 10 wherein a grippingand pulling assembly is provided at said downstream location and pullssaid additional edge portions out of said apparatus while said gates arebeing closed.
 15. The apparatus of claim 10 wherein said additionallongitudinal portions at said upstream location extend through a pair ofupstream clamping members and said additional longitudinal portions atsaid downstream location extend through a pair of downstream clampingmembers and wherein, while said gates are in their closed positions,said upstream and downstream clamping members allow said additionallongitudinal portions to traverse therethrough and, while said gates arein their open positions, said upstream and downstream clamping membersclampingly grip and prevent said additional longitudinal portions totraverse therethrough.
 16. The apparatus of claim 15 wherein saidclamping members are rubber rollers and wherein, while said gates areopening and closing, said rollers guide said additional longitudinaledges as they traverse therethrough.
 17. The apparatus of claim 10further comprising a bulk material measuring apparatus and wherein, whensaid gates are in their open positions, a quantity of bulk material isdelivered between the gates, through the bag opening and into the hagcavity.
 18. The apparatus of claim 10 wherein said plastic film bags areformed from a web of plastic film is folded along a central longitudinalfold line thereby defining said pair of parallel proximate longitudinaledge portions.
 19. The apparatus of claim 1 further comprising a bulkmaterial measuring apparatus and wherein, when said gates are in theiropen positions, a quantity of hulk material is delivered between thegates, through the bag opening and into the bag cavity.
 20. Theapparatus of claim 1 wherein said plastic film bags are formed from aweb of plastic film is folded along a central longitudinal fold linethereby defining said pair of parallel proximate longitudinal edgeportions.